Low pressure is not the key to drilling in stainless steel. 304 or 316 are both soft materials in an annealed state, as soft at mild steel or aluminum. Both materials work harden badly if rubbed but not cut. You start with a 35ksi material and work harden it to 80ksi, about the same as hard alloy steel. You must cut at least 0.001 per cutting edge, and preferable 0.002 to prevent this from happening. That is why steady feed (preferably power feed) from a drill press is highly desirable. In a CNC machine with very reliable feed rate I can drill hundreds of holes through stainless with an ordinary HSS or cheap cobalt bit without sharpening. SS does generate a lot of heat and you want to keep the tool cool, however most of the problems people have are in not cutting the material, but rubbing it and work hardening it. The only way to get sufficient pressure with a bit over about 1/4 is to step up the size incrementally so all the pressure is concentrated on a small cutting edge. If you use light pressure you may eventually wear through the material, but it is a lot of extra effort and will ruin the bit.
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